It's the easiest game to import models and world data from because it uses almost exactly the same file structures as Mafia. The missions all have a scene.4ds, scene2.bin and tree.klz just like Mafia and the scene2s can be opened in DC||ED and viewed properly.

This is common knowledge, but the reason the two games are so similar is because Mafia was built off H&D 1. The engine seen in Mafia Alpha is the engine from H&D 1, but later they realised it wasn't practical for a number of reasons so they created the LS3D engine from scratch to replace it._________________